Balloon with radiopaque adhesive

ABSTRACT

A radiopaque balloon with a composite wall having a radiopaque adhesive affixing inner and outer layers of the balloon. The radiopaque adhesive provides a radiographic image of the balloon wall with or without the use of a radiopaque contrast media to inflate the balloon. A radiographically fainter image is provided as the balloon is inflated with well-defined edges of a balloon image, and the total radiopacity of the balloon does not change as the balloon is inflated. Also, a method of imaging a balloon wall and a method of imaging a radiopaque adhesive between two layers of a balloon wall are provided.

TECHNICAL FIELD

The subject invention relates to balloons having a radiopaque adhesiveand, more particularly, to layered non-compliant medical balloons with aradiopaque adhesive between balloon layers.

BACKGROUND ART

Existing balloons that are imaged with an imaging system are believed toprovide a faint image due to the minimal ability of the balloon wall toabsorb or reflect imaging radiation. Such balloons are also believed toprovide an image that is not significantly distinguishable fromsurrounding structures and tissues, and to provide an image that doesnot readily indicate the inflation status of the balloon or the positionof the balloon wall without the use of an imaging fluid. Accordingly,the location and inflation status of such balloons are enhanced byinflating the balloon with a fluid containing a material that provides amore pronounced image. A shortcoming of such inflation-dependent imagingmethods is that the image obtained is of the fluid within the balloonand not of the balloon itself. It is also believed that imaging fluidsthat provide an adequate image also possess a viscosity that undesirablyincreases the time required to inflate and deflate the balloon when thefluid is delivered to the balloon through a narrow lumen. Anothershortcoming is that such imaging fluids are more expensive and requiremore preparation time as compared to less viscous and pre-made fluidssuch as physiological saline.

In conventional radiography, when a balloon is inflated with aninflation fluid containing an imaging fluid such as contrast media, thecontrast media presents the strongest image at the center portion of theimaged balloon and the weakest image at the edges of the radiographicimage. This is because the x-rays traveling through the center of theballoon pass through a greater quantity of contrast media than at theperipheral edges of the balloon image. This difference results in animage of the fluid in the balloon that has a strongly-imaged center andundesirably faint edges of the image, that is believed to provide anundefined or unclear image of the peripheral edge of the balloon, thusmaking it difficult to determine the exact edge of the balloon, reducingthe precision of the placement of the inflated balloon, and making itdifficult to determine whether the balloon has encountered anyconstrictions in the vessel being dilated.

It is thus desirable to provide a balloon that does not requireinflation with an imaging fluid, and to provide a balloon that permitsdirect imaging of the balloon with or without the use of an imagingfluid.

DISCLOSURE OF THE INVENTION

A balloon and catheter are provided that includes a balloon wall withinner and outer layers with a radiopaque adhesive disposed between andaffixing the inner and outer layers. The radiopaque adhesive includes anadhesive base and a radiopaque material dispersed in the adhesive base.Alternatively, the adhesive base itself is composed of an intrinsicallyradiopaque polymeric material with or without another radiopaquematerial dispersed in the adhesive base. The balloon preferably alsoincludes layers of fibers that reinforce the balloon, and the fibers arepreferably disposed between the inner and outer layers of the balloonwall within or between layers of the radiopaque adhesive. In analternative embodiment, the fibers are arranged in a pattern on theballoon, as layers formed over each other as a weave or braid within afiber layer, or woven or braided together to form a single fiber layer.In another embodiment, the radiopaque adhesive is disposed within theballoon wall to form a pattern.

The balloon is preferably a compliant balloon or, more preferably, asemi-compliant balloon. Compliant balloons allow for the doubling of theouter diameter of the balloon when inflated from an operating pressureto a rated burst pressure, and are made of latex, for example.Semi-compliant balloons provide for an increase in the balloon outerdiameter by 10-15%, and are made of Nylon, for example. The balloon ismost preferably a non-compliant balloon that inflates to a predeterminedsize and shape with a predetermined surface area, circumference, orlength. The preferred non-compliant balloon preferably provides for anincrease in an inflated outer diameter that is within 5% of a nominalballoon diameter. The balloon is also preferably a high-pressure balloonhaving a rated burst pressure of 20 atm or greater, for example.Alternatively, the balloon is a low-pressure balloon having a ratedburst pressure of less than 6 atm.

The balloon preferably has a predetermined total radiographic quantitythat is the total amount of radiopaque material present in the structureof the entire balloon, which includes the radiopaque material present inthe adhesive of the balloon wall and does not include radiopaquematerial that is temporarily added to the balloon such as for inflation.When using a non-radiopaque inflation fluid, the balloon as a wholecontains the same amount of radiopaque material regardless of inflationstate as the total quantity of the radiopaque material within theballoon wall remains constant. The balloon preferably also possesses aradiographic density that is a ratio of the total radiographic quantityrelative to the volume of the balloon, and which is subject to change asthe balloon increases or decrease volume between the uninflated andinflated states of the balloon as the total quantity of the radiopaquematerial in the balloon remains constant while the balloon volumechanges. The balloon also preferably provides a total radiographic imageintensity that characterizes the image that the entire balloon presentsto an imaging device when viewed, and that becomes less intense as theballoon is inflated and the fixed quantity of radiopaque material in theballoon is dispersed over a greater volume. The radiographic imageintensity can also characterize the image present at only a portion ofthe balloon, such as at the center of the balloon image presented by animaging system viewing the balloon from a side of the balloon.

Also provided is a fiber-reinforced balloon with a wall that includes aradiopaque adhesive that does not add to the radial thickness of thewall. The fibers of the fiber-reinforced balloon are preferably disposedin layers with one fiber layer over and contacting an adjacent fiberlayer. Preferably, the radiopaque adhesive is disposed in spaces betweenadjacent fibers of the fiber layers to affix one fiber layer to anadjacent fiber layer.

Also provided is a method of imaging a balloon wall, and a method ofimaging a radiopaque adhesive between two layers of a balloon wall. Apreferred method of making a balloon wall with a radiopaque adhesive isprovided that includes applying a radiopaque adhesive between two layersof a balloon wall. Also provided is a method of treating a region of ahuman body by imaging a wall of a balloon, and a method of imaging aradiopaque adhesive disposed between two layers of a balloon wall.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated herein and constitutepart of this specification, illustrate exemplary embodiments of theinvention, and, together with the general description given above andthe detailed description given below, serve to explain the features ofthe invention.

FIG. 1 is an isometric view of a portion of an exemplary catheter and ofan exemplary balloon.

FIG. 2 is a cross-sectional view of the catheter and balloon of FIG. 1.

FIG. 3 is a cross-sectional view of a portion of the balloon of FIG. 1,and an enlarged view of a portion of the balloon of FIG. 2.

FIGS. 4A-4D are cross-sectional views illustrating the manufacture ofanother embodiment of a balloon. FIG. 4E is a cross-sectional view ofthe balloon wall of FIG. 4D. FIGS. 4F-4G are the same views presented inFIGS. 4D and 4E, respectively, but illustrating another exemplaryembodiment.

FIGS. 5A-5B are plan and cross-sectional views of a portion of acatheter and a deflated exemplary balloon.

FIGS. 6A-6B are plan and cross-sectional views of the catheter andballoon of FIGS. 5A and 5B with an exemplary implantable device.

FIGS. 7A-7B are cross-sectional plan views of a deflated and inflatedexemplary balloon, illustrating the radiopaque image provided by theballoon wall.

FIG. 8A illustrates x-ray imaging directed at the side of a balloon witha radiopaque adhesive and FIG. 8B represents the image intensityprovided by the x-ray imaging.

FIG. 9A illustrates x-ray imaging directed at the side of a conventionalballoon filled with a radiopaque contrast media and FIG. 9B representsthe image intensity provided by the x-ray imaging.

MODE(S) FOR CARRYING OUT THE INVENTION

The description provided below and in regard to the figures applies toall embodiments unless noted otherwise, and features common to eachembodiment are similarly shown and numbered.

Provided is a catheter 10 having a distal portion 11 with a balloon 12mounted on a catheter tube 14. Referring to FIGS. 1 and 2, the balloon12 has a central section 16 and conical end sections 18, 20 that reducein diameter to join the central section 16 to the catheter tube 14. Theballoon 12 is sealed to catheter tube 14 at balloon ends 15 on theconical end sections 18, 20 to allow the inflation of the balloon 12 viaone of more lumens extending within catheter tube 14 and communicatingwith the interior of the balloon. The catheter tube 14 also includes aguidewire lumen 24 that directs the passage of the guidewire 26 throughthe catheter 10. Balloon 12 has a multi-layered balloon wall 28 formingthe balloon 12, and preferably is a non-compliant balloon that has aballoon wall 28 that maintains its size and shape in one or moredirections when the balloon is inflated. The balloon 12 preferably has apre-determined surface area that remains constant during and afterinflation, and also preferably has a pre-determined length andpre-determined circumference that each, or together, remain constantduring and after inflation. The balloon 12 also preferably unfolds to apre-determined diameter when inflated. Balloon 12 is also preferablynon-compliant in that it maintains a pre-determined shape when inflated.

The balloon wall 28 includes an inner layer 30 and an outer layer 32.Between layers 30, 32 is an adhesive 34 that secures the outer layer 32to the inner layer 30. FIG. 3 illustrates an exemplary arrangement oflayers 30, 32 and adhesive 34. The adhesive 34 preferably includes anadhesive base 35 and a radiopaque material 36 dispersed within theadhesive base 35. The adhesive base 35 is preferably a laminatingadhesive such as a: thermoplastic polyurethane, thermoplastic acrylic,rubber-based adhesive, polyamide, polyvinyl acetate, polyethylene-vinylalcohol copolymer, solvent-borne adhesive, hot-melt adhesive, polyvinylbutyral, cellulosic derivatives such as cellulose-acetate-butyrate,silicone RTV, or other similar flexible adhesives capable of laminatingfilms or bonding plastic materials together. More preferably, theadhesive base 35 is a solvent-borne adhesive of a flexible thermoplasticmaterial, such as a polyurethane, polyamide, or acrylic polymer. Mostpreferably, the adhesive base 35 is a thermoplastic polyurethaneadhesive that is applied as a solution, and re-activated with a solventsuch as a methyl ethyl ketone applied to the dried adhesive base 35. Theplacement of the adhesive 34 between the inner and outer layers 30 and32 preferably provides a barrier between the adhesive and the internalor external environments of the balloon 12, so as to seal and isolatethe adhesive 34 from the patient and limit the patient's contact withthe adhesive.

In an alternative, the adhesive base 35 itself is composed of anintrinsically radiopaque polymeric material that contains higher atomicweight heteroatoms covalently or ionically bound into the polymerstructure, and that imparts radiopacity to the polymer itself. Suchpolymers include polymers that have covalently bonded iodine or brominein the polymer structure. Such polymers also include polymers withionically bonded metals such as cerium, gadolinium, or other rare earthmetals, or barium, bismuth, or other metals that have good radiopacity.Another intrinsically radiopaque polymer includes a polymer that iscapable of complexing a radiopaque compound in the molecular structureof the polymer, such as a polymer that contains functional groups thatbind with and form complexes with radiopaque compounds such as iodine,bismuth compounds, rare earth salts, or other substances that exhibitgood radiopacity. Yet another embodiment includes an adhesive that iscomposed of an intrinsically radiopaque polymer, such as the polymersdescribed above, to which the radiopaque material 36 is added anddispersed throughout the adhesive base 35.

Alternatively, the adhesive base 35 is a two-part adhesive in which thetwo components are applied separately or as a pre-made mixture to theinner or outer layers 30, 32 that interact to form the adhesive base.Examples of two-part adhesives include crosslinked polyurethanes,thermoset acrylic adhesives, epoxies, crosslinked polyureas,polyurethaneureas, two-part silicone rubber adhesives, and othertwo-component adhesive materials. In yet another alternative, theadhesive base is the reaction product of a first and second substance,with the first substance being a component of the inner or outer layers30, 32, and the second substance being applied to the layers 30, 32 tointeract with the first substance to form a two-part adhesive, or toactivate the first substance to form the adhesive. In still anotheralternative, the adhesive base is a substance that is activated by anexternal factor to cause the adhesive base to alter and form theadhesive by the application of heat, pressure, or radiation. Examples ofexternally-activated adhesives include polyamide hot melt adhesives,ethylene vinyl acetate copolymers, thermoplastic polyurethanes, hot-meltadhesives used in lamination, and pressure sensitive adhesives such asacrylic, silicone, and rubber-based pressure sensitive adhesives.

The radiopaque material 36 is distributed in the adhesive base 35 in asufficient quantity to permit imaging of the balloon wall 28 by animaging method. The radiopaque material 36 is preferably a material thatabsorbs or reflects significant quantities of x-ray or otherdiagnostically-significant radiation to render an image during a imagingprocedure. The radiopaque material 36 is more preferably a material thatabsorbs x-rays. Examples of radiopaque materials include dense metalssuch as tungsten, tantalum, silver, tin, platinum, gold, iridium, andsimilar metals known to absorb x-rays. Other examples of radiopaquematerials include inorganic compounds that absorb x-rays. Furtherexamples of radiopaque materials include barium sulfate, bismuthtrioxide, bismuth subcarbonate, bismuth oxychloride, cerium oxide,compounds of tungsten, tantalum, and rare earth metals. Most preferably,the radiopaque material 36 is tungsten. The radiopaque material 36 ispreferably evenly distributed in the adhesive 34. Alternatively, theradiopaque materials are distributed in the adhesive to form patterns,or to facilitate a darker or lighter image at different locations in theballoon wall 28 to form a pattern in the resulting image or tocompensate for areas of the balloon that provide a darker or lighterimage resulting from the changes in the geometry or structure of theballoon or changes in balloon wall thickness, such as at the conical endsections 18, 20 where the diameter of the balloon changes.

The adhesive 34 is preferably a predetermined mixture of the adhesivebase 35 and the radiopaque material 36 distributed within the adhesivebase. The volume of radiopaque material distributed in the adhesive ispreferably used to determine the intensity of the image that resultsduring x-ray imaging. Preferably, the adhesive is composed of 40-98volume-% adhesive base and 2-60 volume-% radiopaque material. Morepreferably, the adhesive is composed of 55-80 volume-% adhesive base and20-45 volume-% radiopaque material. Most preferably, the adhesive iscomposed of 65 volume-% adhesive base and 35 volume-% radiopaquematerial.

The adhesive 34 is preferably placed along the entire length andcircumference of balloon wall 28 to bond the entire mating surfaces ofthe inner and outer layers 30, 32 to each other. Alternatively, theadhesive 34 is disposed at only portions of the wall and anotheradhesive, without the radiopaque material 36, is disposed along theremainder of the balloon wall 28 to form a pattern in the radiopaqueimage of the balloon 12. In another alternative, the quantity ofradiopaque material 36 in the adhesive 34 is varied to form a pattern inthe image of the balloon 12 obtained with an imaging system. Thepatterns of these alternative embodiments preferably form an image oflines or bands in the balloon wall 28. In yet another alternative, thequantity of the radiopaque material in the adhesive is modified toprovide a consistent image of the inflated or deflated balloon 12 withan imaging system, by controlling the placement of the radiopaquematerial 36 to compensate for or minimize variations or patterns createdin the image of the balloon 12 caused by variations of balloon geometryor by the presence of a device carried on the balloon.

The balloon wall 28 is preferably formed with successive layers.Referring to FIG. 3, the balloon is preferably formed by providing theinner layer 30, applying the adhesive 34, and providing the outer layer32. The adhesive 34 is preferably applied onto the exterior of the innerlayer 30 by spraying, dipping, brushing, or by other suitable means.Referring to FIG. 3, the adhesive 34 is preferably a single layer thatis subsequently covered by the outer layer 32 to form the balloon wall28. In an another embodiment, reinforcing fibers or filaments are addedbetween the inner and outer layers 30, 32 to increase the balloonstrength under pressure or to control the compliance and shape of thefinished balloon

In a preferred embodiment, the balloon wall is formed with successivelayers disposed on a base balloon. Referring to FIG. 4A, a base balloon38 is provided as an initial balloon structure in the manufacture of theballoon. The base balloon is preferably composed of any thermoplastic orthermoset material that is capable of being formed into the desiredballoon shape. Examples of base balloon materials include polyamides,polyesters, polyurethanes, polyethylene, polypropylene,polyamide-polyether block copolymers, polyimides, crosslinkedpolyethylene, ionomers such as Surlyn®, crosslinked polyurethanes, andother similar polymers that possess the desired properties of strength,flexibility, and distensibility for use in a compliant or non-compliantballoon. The base balloon 38 is preferably a PET tube that is stretchedunder heat and pressure into the desired balloon form, such as to form acylinder having the central section 16, conical end sections 18, 20, andballoon ends 15 as illustrated in FIG. 1.

After formation of the base balloon 38, adhesive is applied to theexterior surface of the base balloon 38 as a first adhesive layer 40.The first adhesive layer 40 is preferably applied onto the exterior ofthe base balloon 38 by spraying, dipping, brushing, or by other suitablemeans. Preferably, although not shown in FIG. 4A, the first adhesivelayer 40 includes a radiopaque material distributed within the adhesive.In an alternative embodiment, the first adhesive layer 40 does notinclude a radiopaque material.

Referring to FIG. 4B, a series of first fibers 42 are applied to thebase balloon 38 to form a fiber layer, and affixed to the base balloon38 by the first adhesive layer 40. Preferably, some of the adhesive offirst adhesive layer 40 moves to partly fill the spaces formed betweenadjacent fibers 42, with only a minimal or negligible amount of adhesiveremaining directly between the fibers 42 and the outer surface of baseballoon 38. The movement of the adhesive to the spaces between adjacentfibers 42 keeps the adhesive from contributing to the wall thickness ofthe balloon wall while still providing the desired adhesion propertiesto affix the first fibers 42 to the base balloon 38. The first fibers 42are preferably disposed in the direction of the longitudinal axis of theballoon or catheter. More preferably, the first fibers 42 extend alongthe exterior surface of the balloon base 38 for different or varyinglengths. Most preferably, some of the fibers of first fibers 42 extendalong the length of the only the central section 16 of the balloon, andsome of the first fibers 42 extend along the entire length of theballoon to cover the central section 16 and the conical end sections 18,20. The use of varying fibers lengths for the first fibers 42 providesfor fewer fibers at the conical end sections 18, 20, which prevents thefiber layer formed by the first fibers 42 from bunching up or creasingas the diameter of the balloon reduces along the length of the conicalend sections 18, 20.

Any high strength fibers or filaments are preferably used to impart thedesired properties to the balloon. Examples of suitable fibers includeultrahigh molecular weight polyethylene such as Spectra® or Dyneema®fibers, polyamide fibers, polyimide fibers, ultrahigh molecular weightpolyurethane fibers such as Technora®, fibers made from polyesters orpolypropylene, or finely drawn strands of metals such as stainless orhigh tensile steel. The first fibers 42 are preferably ultra-highmolecular weight polyethylene or Technora® fibers having a filamentdiameter of about 12 microns that has been flattened to a rectangularprofile of about 0.0005 of an inch by 0.020 of an inch.

Referring to FIG. 4C, more adhesive is applied to the exterior of thecomposite formed by based balloon 38, first adhesive layer 40, and firstfibers 42. Preferably, the adhesive 34 with the radiopaque material 36is applied to the exterior of the first adhesive layer 40 and firstfibers 42 to form an intermediate adhesive layer 43. The adhesive of theintermediate adhesive layer 43 is preferably applied as a spray, ordeposited by dipping into a bath, or by brush or other suitable means.Applying by spray is more preferable. In an alternative, theintermediate layer 43 is applied to form a radiopaque pattern bycontrolling the placement of the adhesive 34 on the composite, or by theuse of another adhesive that does not have a radiopaque property andthat is disposed over the composite in a desired pattern.

Referring to FIG. 4D, a second fiber 44 is disposed over theintermediate adhesive layer 43 and affixed to the underlying firstfibers 42 by the adhesive 34. The second fiber 44 is preferably composedof any of the aforementioned fiber materials and is more preferably asingle ultra-high molecular weight polyethylene or Technora® fiberidentical to the first fibers 42. The second fiber 44 is preferablywound circumferentially around the base balloon 38 to form acircumferential fiber layer helically extending along the longitudinallength of the balloon 12. Referring to FIGS. 4D-4E, a second adhesivelayer 46, preferably identical to the first adhesive layer 40, isapplied to the exterior of the composite of base balloon 38, layers 40and 43, and fibers 42 and 44. The fibers are preferably disposed aslayers with the layer of the second fiber 44 disposed over the layer offirst fibers 42. Alternatively, the fibers form a weave or braidedstructure within a single layer, with the first fibers 42 disposed toform a first weave layer and the second fiber 44 disposed to form aweave with itself or with another fiber to form a second weave layer. Inanother alternative, the first fibers 42 and the second fiber 44 jointogether a weave or braided structure to form a single weave or braidedlayer.

Although not shown in FIGS. 4D-4E, the second adhesive layer 46 alsopreferably bonds to a protective outer film (not shown) of the balloon12. It is preferable to include a protective outer film on the exteriorsurface of the balloon to provide abrasion resistance to the balloonsurface and to protect the underlying fibers. Preferably, this film isan abrasion resistant material. Examples of abrasion resistant materialsinclude polyesters, polyamide, polyamide-polyether block copolymers,polyurethanes, ionomers such as Surlyn®, polyethylene, polypropylene,and crosslinkable materials such as polyurethanes or polyethylene.Preferably, a polyether block copolymer such as Pebax® is used as theabrasion resistant material. In an alternative embodiment, theprotective outer film is formed by melting and fusing the secondadhesive layer 46 when heat is applied during manufacture. In anotheralternative, the protective outer film includes a radiopaque materialdispersed within the film to impart additional radiopacity to theballoon.

In another alternative, a protective coating is applied to the balloon,instead of by bonding the radiopaque adhesive to a film or by forming aprotective film from the adhesive itself Examples of protective coatingsproviding abrasion resistance include epoxies, polyurethanes,polyesters, alkyd resins, polyvinylbutyral, cellulose nitrate, polyvinylacetate, phenolic resins such as phenol-formaldehyde resins, and aminoresins such as amino-formaldehyde resins. The protective coatingpreferably includes some radiopaque material dispersed within it toimpart additional radiopacity to the balloon.

In order to consolidate the laminated composite structure (of baseballoon, fibers, adhesive layers, and protective outer film or coating)into a fused balloon wall, the composite is exposed to conditions thatcause the layers to intimately bond together. Preferably, the compositeof balloon 12 is heated in a die using heat and pressure to fuse thecomposite materials into a consolidated structure. Preferably, if theadhesive is a thermoplastic material, such as a thermoplasticpolyurethane, the application of heat will also soften the adhesive andcause it to flow and bond to the composite materials of the balloon.Also preferably, if the adhesive contains a catalyst or is a two-partmaterial that requires reaction of the two components in order to cure,the application of heat provides the means to accelerate the curingprocess.

Each layer of adhesive is preferably applied in a single application.Alternatively, each layer of adhesive is applied as a composite ofmultiple applications to achieve a desired layer thickness or a desireddisposition of radiopaque material. The adhesive 34 preferably has aradial thickness of 2-100 microns, more preferably has a radialthickness of 3-50 microns, and most preferably has a radial thickness of10-40 microns. In a preferred embodiment having fiber reinforcement, theintermediate layer 43 has a thickness that allows radial contact betweenthe first fibers 42 and second fiber 44 so as to cause the adhesive 34of the intermediate layer 43 to move into and occupy the spaces betweenthe adjacent first fibers 42 or adjacent windings of the second fiber44, thereby allowing the intermediate layer 43 to be present in theballoon wall 28 but not add to the radial thickness of the balloon wall28. FIGS. 4F and 4G illustrate an alternative embodiment to that shownin FIGS. 4D and 4E, respectively, in which the intermediate adhesivelayer 43 is present but does not add to the radial thickness of theballoon wall 28. In an alternative, some of the adhesive layers, whichhave radiopaque or non-radiopaque properties, are comprised of materialsthat soften and flow during the lamination process.

Other embodiments of the radiopaque balloon are similarly constructedbut without the reinforcing fibers. In this alternative embodiment, theballoon has a base balloon, a layer of radiopaque adhesive on theoutside surface of the base balloon, and a final protective layer suchas a film or coating over the exterior surface of the radiopaqueadhesive. The radiopaque adhesive imparts radiopacity to the balloon andbonds the base balloon to the protective outer layer.

The adhesive 34 is alternatively applied in a pattern. The patterns arepreferably made with the selective application of adhesive 34 whenapplying the intermediate adhesive layer 43, for example, with the useof a narrow PTFE tape that is wrapped over the first fibers 42 to maskareas of the balloon composite prior to the application of theintermediate adhesive layer 43. The PTFE tape is then removed after theapplication of the intermediate adhesive layer 43 to expose areas thatdo not have the adhesive 34. A layer of a non-radiopaque adhesive isthen applied that does not have the radiopaque material 36 to coat theentire balloon composite, thereby placing an additional non-radiopaqueadhesive layer over the first fibers 42 and the intermediate adhesivelayer 43 and to fill in areas that were covered by the PTFE tape.

Alternatively, the manufacturing process illustrated in FIGS. 4A-4E andFIGS. 4F-4G is accomplished with the use of a mold or mandrel in placeof the base balloon 38. The mold or mandrel is subsequently removedafter the lamination of the balloon 12 to leave a balloon wall that doesnot have the base balloon 38, leaving the first adhesive layer 40 andfirst fibers 42 to form the interior surface of the balloon 12.

In another alternative, the balloon 12 includes a layer of markermaterial, such as a marker strip, marker filaments, or marker ring,preferably between the first fibers 42 and second fiber 44 atpredetermined locations such as at the balloon ends 15 to formradiopaque markers identifying specific locations on the balloon 12. Theradiopaque markers preferably have a different radiopacity than theradiopacity of the remainder of the balloon wall 28. The marker strips,filaments, or rings are preferably made from a material that exhibitsthe preferred properties of radiopacity, flexibility, malleability, andprocessability. Suitable materials for use as a marker include tantalum,tin, silver, gold, platinum, rhenium, iridium, palladium, hafnium,tungsten, lanthanum, and other metals that absorb x-rays. Preferablematerials include silver and tin.

The deflated balloon 12 is preferably folded and wrappedcircumferentially about itself to provide a reduced profile to theballoon 12. The wrapped balloon 12 preferably assumes a profile havingan outer diameter that is similar to or approximately matching the outerdiameter of the catheter tube 14. FIGS. 5A-5B illustrate an exemplaryfolded balloon. Referring to FIGS. 6A-6B, a portion of the exterior ofthe wrapped balloon 12 is formed to hold a medical device 48 in acollapsed state, which is preferably a stent that is compressed orcollapsed to a delivery diameter. The inflation of the balloon 12preferably applies an expanding force to the interior of the medicaldevice 48 to cause it to expand to a greater diameter. After the medicaldevice 48 has been expanded, and if designed to maintain a stableexpanded configuration, the balloon 12 is preferably deflated andwithdrawn from the interior of the medical device 48, therebydisengaging from the medical device 48.

Referring to FIG. 7A, the deflated balloon 12 is preferably insertedinto a vessel 52 and positioned relative to a region of interest 50.Referring to FIG. 7B, once positioned, the balloon 12 is preferablyinflated to cause the exterior surface of the balloon to contact andpress against the walls of the vessel 52 in the region of interest 50.The an alternative embodiment having a medical device 48 mounted on thedeflated balloon 12, the inflation of the balloon 12 expands the medicaldevice 48 to cause the exterior of the medical device to press againstthe vessel walls to achieve a therapeutic effect. The balloon 12 ispreferably inflated with an inflation fluid delivered to the interior ofthe balloon through a lumen.

The quantity of radiopaque material 36 in the balloon wall 28 is fixedwhen the balloon wall is manufactured, which defines the totalradiographic quantity for the balloon 12. Referring to FIGS. 7A and 7B,the constant quantity of radiopaque material in the balloon 12 providesa radiographic density that exhibits a relatively intense averageradiopaque image (as compared to the radiopaque image of the inflatedballoon) when the balloon is wholly or partially folded, deflated,empty, collapsed, and/or minimally filled with an inflation fluid, suchas saline, because the radiopaque material 36 within the adhesive 34 ofthe balloon 12 will be closely packed together in the folded balloon 12.The deflated balloon 12 will also have a relatively greater radiopaquedensity as compared to the inflated balloon. The center portion of animage of the balloon 12 will also provide a radiographic image intensitythat exhibits a relatively less pronounced radiopaque image when theballoon is fully inflated with inflation fluid because the radiopaquematerial 36 in the balloon wall 28 will have moved apart to a greaterradial distance from the longitudinal axis of the catheter during theinflation process to cause a relative lighter radiopaque image. Also theedges of the balloon in an image of the balloon will maintain acomparatively intense image during and after inflation because the imageof wall is obtained at an oblique angle in which the imaging radiationpasses through or reflects off the wall in a direction that is nearlyparallel to the surface of the wall, which causes the radiation to beaffected by additional radiopaque material as compared to when theradiation passes through the wall at a right angle. The inflated balloon12 as a whole will also have a relatively reduced radiographic imageintensity as the balloon inflates because of the increase in balloonvolume resulting from the inflation of the balloon. The balloon 12 as awhole will also provide a varying radiopaque image as the balloon 12progresses between the radiopaque extremes provided in the deflated andinflated states of the balloon 12, with a more intense radiopaque imageprovided with the deflated balloon and a less intense radiopaque imageprovided with the inflated balloon. Furthermore, the center of the imageof the balloon will exhibit a relatively intense image when deflated anda relatively less intense image when inflated, and the edges of theimage of the balloon will exhibit a relatively constant radiopaqueimage.

The balloon 12 thus has an radiographic density that changes when theballoon 12 transitions between deflated and inflated states, whichdirectly corresponds to volume of the balloon at any point relative tothe fixed quantity of radiopaque material 36 in the balloon wall 28.Specifically, the image of the center of the radiopaque balloon 12becomes radiographically lighter as the balloon is inflated, whereasconventional balloons that are not radiopaque become radiographicallydarker at the center of the balloon image because of the presence of aradiopaque inflation fluid.

The radiographic density of the entire balloon 12 is determined bycomparing the fixed quantity of radiopaque material 36 to the entirevolume of the balloon 12. As the total quantity of radiopaque materialin the balloon wall 28 is constant, changes in balloon volume cause theradiographic density to change. Referring to FIG. 7A, the radiographicdensity of the folded balloon 12 is relatively high because the fixedvolume of radiopaque material 36 is contained in a relatively smallvolume of the folded balloon 12. Referring to FIG. 7B, the radiographicdensity of the inflated balloon 12 is relatively low because the fixedvolume of radiopaque material 36 is contained in relatively large volumeof the inflated balloon 12. The average change in radiographic densitybetween a fully-deflated, folded balloon and a fully-inflated balloon isproportional to the change in the diameters of the balloon in these twoconditions.

It is believed that, during a typical medical procedure, the balloon istypically imaged on a fluoroscope from a position perpendicular to themain balloon axis. From this perspective, the distribution of radiopaquematerial in the balloon wall provides an image that is advantageouslynot uniform. The radiopaque balloon 12 provides an image that appears tobe more radiopaque material at and very near the edges of the balloonimage, and less in the center region of the balloon. As such, the imageintensity of the center region of the balloon is diminished even furtherwhen the balloon is inflated. Table 1 below shows the change in averageradiographic density for various size balloons of a typicalconstruction, as well as the change that occurs in the center region ofthe balloon.

TABLE 1 Change in radiographic image intensity resulting from inflationfor various balloon sizes Decrease in balloon Decrease in radiographictotal balloon image intensity in radiographic center region of InflatedDeflated image intensity balloon image balloon outer balloon outer whenballoon is when balloon is diameter diameter inflated from inflated from(mm) (mm) deflated state (%) deflated state (%) 5 2.03 59.4 71.3 6 2.0366.2 76.1 7 2.03 71.0 79.5 8 2.03 74.6 82.1 9 2.23 75.2 82.5 10 2.2377.7 84.2 12 2.41 79.9 85.8 14 2.33 83.4 88.2 16 2.64 83.5 88.3 18 2.6985.1 89.4 20 2.95 85.3 89.6 22 3.3 85.0 89.4 24 3.99 83.4 88.2 26 3.9984.7 89.1

The decrease in total radiographic image intensity between thefully-deflated and fully-inflated balloon preferably ranges from 35-95%,and more preferably ranges from 60-90%.

The distribution of radiopaque adhesive in the balloon, as viewed undera fluoroscope, is an important feature of this invention, as compared toa non-radiopaque balloon filled with radiopaque contrast media. FIGS. 8and 9 illustrate this effect. Since the x-rays used for imaging passthrough the balloon in a direction roughly perpendicular to thelongitudinal axis of the balloon, the amount of radiopaque adhesive thatthe x-ray beam encounters is significantly greater at and very near theedges of the balloon, as compared to other areas of the balloon imagedisposed within the edges of the balloon image. This greater interactionwith x-rays at the edges of the balloon image yields an image of aballoon that has defined edges in the image. The increase inradiographic density at the balloon image edge, compared to the balloonimage center, is a function of the diameter of the inflated balloon andthe thickness of the radiopaque adhesive layer. Table 2 shows thedifference in radiographic image intensity presented by the edges of theimaged balloon as compared to the center of the imaged balloon, forseveral balloon sizes and radiopaque adhesive thicknesses. Increases inradiographic image intensity at the imaged balloon edge range from 560%to over 2000% as compared to the imaged balloon center.

TABLE 2 Radiographic image intensity comparison between balloon imageedge and balloon image center Thickness of radiopaque adhesiveencountered by x-rays directed at the imaged balloon edge fromRadiopaque a position Difference between image adhesive orthogonal tointensity at balloon image Balloon thickness the balloon edge comparedto imaged size (mm) (mm) axis (mm) balloon center (%) 5 0.025 0.50061001 6 0.025 0.5483 1097 7 0.025 0.5921 1184 8 0.025 0.6329 1266 9 0.0250.6713 1343 10 0.025 0.7075 1415 12 0.025 0.7750 1550 14 0.025 0.83701674 16 0.025 0.8948 1790 18 0.025 0.9490 1898 20 0.025 1.0003 2001 220.025 1.0491 2098 24 0.025 1.0957 2191 26 0.025 1.1404 2281 5 0.0750.8693 580 6 0.075 0.9516 634 7 0.075 1.0274 685 8 0.075 1.0980 732 90.075 1.1643 776 10 0.075 1.2270 818 12 0.075 1.3437 896 14 0.075 1.4511967 16 0.075 1.5510 1034 18 0.075 1.6449 1097 20 0.075 1.7337 1156 220.075 1.8181 1212 24 0.075 1.8988 1266 26 0.075 1.9763 1318

The intensity of the imaged balloon edge of a balloon with a radiopaqueadhesive is comparable to the intensity of the imaged balloon edgeproduced by a conventional non-radiopaque balloon that is filled with aradiopaque contrast media. FIGS. 8A-9B illustrate the distribution ofradiographic image intensity that is observed in this comparison. Asillustrated in FIG. 8A, illustrating x-rays directed at the side of aballoon with a radiopaque adhesive, and FIG. 8B, representing the imageintensity provided by the x-ray imaging, the balloon image intensity ismost intense at the imaged edges of the balloon. In comparison, FIG. 9A,illustrating x-rays directed at the side of a conventional balloonfilled with a radiopaque contrast media, and FIG. 9B, representing theimage intensity provided by the x-ray imaging, the balloon imageintensity is nonexistent at the edges of the balloon and minimallyintense adjacent to the imaged edges of the form presented by thecontrast media. Conventional balloons using contrast media are thusbelieved to provide a fuzzy and poorly defined imaged balloon edgebecause the x-rays do not image the balloon itself, and because thecontrast media imaged near the edges of the form outlined by thecontrast media has a minimal or negligible thickness as compared to thethickness presented at the center of the imaged balloon.

Referring to FIGS. 7A and 7B, the balloon wall 28 itself (disregardingany inflation fluid or the volume of the balloon) has an constantballoon wall radiographic density that does not change relative to theinflation state of the balloon 12, and that provides an image of theballoon 12 in all inflation states. When the deflated balloon 12 isfolded, the balloon wall 28 exhibits the same total radiopacity as whenthe balloon is inflated because the density of the radiopaque material36 in the balloon wall 28 has not changed. The radiopaque imagepresented of the folded balloon wall 28, as illustrated in FIG. 7A, isthe additive radiopacities of the folded portions of the balloon wall28, and the total radiopacity of the folded balloon is thus a functionor factor of the radiopacity contribution of each fold of the balloonwall.

The inflation of the balloon 12 is preferably achieved by supplying theinflation fluid to the interior of the balloon 12 via the catheter tube14. The inflation fluid is preferably a mixture of a physiologicalsaline solution and a radiopaque contrast media, or pure physiologicalsaline solution. Available contrast media include iodinated compoundsthat are either monomeric or dimeric in structure, which includesacetrizoate (Diaginol, Urokon), diatrizoate (Angiographin, Renografin,Urovison), iodamide (Uromiro), ioglicate (Rayvist), iothalamate(Conray), ioxithalamate (Telebrix), iotrolan (Isovist), iodixanol(Visipaque), iohexol (Omnipaque), iopentol (Imagopaque) and ioversol(Optiray). Another type of contrast media includes chelates of rareearth or other heavy metal species, such as gadolinium, holmium,manganese or dysprosium provided in commercially-available products suchas Dotarem, Omniscan, Eovist, Prohance, and Multihance products. Theinflation fluid is preferably prepared to have a concentration ofradiopaque fluid that is less than 50%. The inflation fluid morepreferably has a concentration of radiopaque fluid that is from 0% (puresaline solution) to approximately 40%, and yet more preferably in rangeof approximately 0-20%, and still more preferably in a range ofapproximately 0-5%, and most preferably at a concentration of 0%.

Generally, it is believed that radiopaque fluids have a viscosity thatis greater than the viscosity of pure physiological saline. Likewise, itis believed that mixtures of saline with radiopaque fluids haveviscosities that are less than undiluted radiopaque fluid but stillgreater than the viscosity of pure saline. It is also believed that thegreater viscosities of radiopaque fluids and saline/radiopaque fluidmixtures cause such fluids to move, at a given pressure, more slowlythrough tubing than the movement observed with pure saline under thesame conditions. The greater viscosities of radiopaque fluids, comparedto pure saline, thus require greater head pressures to push theradiopaque fluids through tubing, and greater head pressures to achievethe balloon inflation times achieved with saline under the sameconditions. The relatively higher viscosities of radiopaque fluids thuscause the balloon 12 to fill more slowly as compared to a ballooninflated with pure saline. This effect becomes even more pronounced withballoon deflation. This is because, unlike inflation, it is not possibleto apply a high pressure on the fluid in the balloon to force it to flowout of the catheter during deflation. The maximum pressure available forforcing fluid out is limited to a vacuum that depends in the ambientatmospheric pressure available (14.7 psi or 1 atmosphere). Deflation ofthe balloon can thus take a considerable time depending on the catheterconstruction and balloon size. All of these factors are believed toincrease the time and/or effort required to complete a medical procedureinvolving the use of a conventional balloon and radiopaque imaging, andan increase in the time required to achieve balloon inflation ordeflation.

The relation of inflation fluid density (concentration of radiopaquefluid in saline) to balloon deflation time is illustrated in Table 3.

TABLE 3 Relation of inflation fluid density and balloon deflation timeConcentration of radiopaque Mean deflation time of fully- fluid insaline (%) inflated balloon (seconds) 0% 6.20 25% 8.18 50% 11.45 75%18.30 100% 53.29

Accordingly, the exemplary radiopaque balloon provides advantages overexisting balloons that do not have a radiopaque balloon wall. Theexemplary balloon provides faster inflation and deflation times becausethe balloon produces an image with an imaging system while beinginflated with a less viscous fluid as used with convention balloons.Also, the exemplary balloon provides a balloon that uses less or noradiopaque fluid, and thus provides a simpler and less expensive methodfor inflating and imaging a balloon. When the inflation solution is puresaline solution, the time and expense of mixing solutions is eliminatedentirely from the balloon inflation and deflation process.

The reduced deflation time, and ease with which the balloon can bedeflated, with a balloon containing a radiopaque adhesive in the balloonwall, also avoids a potentially serious complication that can occurduring a medical procedure. It is believed that viscous fluidscontaining contrast media are more likely to permit a balloon to appearto deflate but leave a significant quantity of media in theapparently-deflated balloon. When the catheter is subsequently moved toinitiate extraction of the catheter from the patient, by repositioningthe apparently-deflated balloon in an introducer tube, the mediaremaining in the apparently-deflated balloon can be forced towards thedistal end of the balloon to inflated the distal-most end of the balloonthat resists complete withdrawal of the balloon into the introducertube. This condition is further exasperated because aninflation/deflation eyehole permitting the further deflation of theballoon can be pinched shut by the pressure exerted on the balloon bythe constructing introducer tube as it presses against the bolus ofmedia trapped in the balloon. As can be appreciated, the results of sucha situation could create an adverse health risk for the patient, rupturethe balloon and release media, and increase the length and complexity ofthe medical procedure.

Additional examples of a balloon with a radiopaque adhesive in a balloonwall are provided below.

Example 1

A radiopaque adhesive was prepared by adding the following componentsinto a glass mixing vessel:

1) 54 grams of a polyurethane laminating adhesive available as Tecoflex®1-MP adhesive having approximately 8.5 wt. % polyurethane in solvent;

2) 24.5 grams of tungsten powder, 0.5 micron nominal particle size; and

3) 36.6 grams of methyl ethyl ketone (MEK).

The components were mixed to produce an adhesive with a homogeneouscomposition of approximately 25 wt % solids.

Polyethylene terephthalate (PET) angioplasty balloons, measuring 12 mmin diameter and with a double wall thickness of approximately 0.002 ofan inch, were mounted on mandrels to allow the balloons to be inflated.The inflated balloons were sprayed with the radiopaque adhesive todispose a uniform quantity of adhesive over the surface of the balloons.The adhesive was rapidly dried on the surface of the balloon. The driedadhesive contained approximately 26 volume % of tungsten and 74 volume %polyurethane.

The balloons were then wrapped helically with a thin strip ofpolyether-polyamide copolymer film commercially available as Pebax®. Thefilm thickness, of approximately 0.0005 of an inch, was stretched duringwrapping to further reduce the thickness. Once wrapped, the balloonswere placed in laminating dies of a size and shape to allow heat andpressure to be applied to the balloon surface. Balloons were heated to atemperature of approximately 220 degrees F. with pressure applied to thesurface of the balloon to cause the radiopaque laminating adhesive toflow and consolidate the balloon and Pebax® film.

The result was a radiopaque angioplasty balloon with a double wallthickness of 0.0045 of an inch. The balloons were examined by x-rayimaging and showed excellent visibility without the need to fill themwith contrast media. A control of conventional PET balloons of the samesize did not exhibit a visible image under the same x-ray imaging.

Example 2

A radiopaque laminating adhesive was prepared by adding the followingcomponents into a glass mixing container:

1) 61 grams of a polyurethane laminating adhesive available as Tecoflex®1-MP adhesive;

2) 14.6 grams of bismuth trioxide powder;

3) 24.4 grams of MEK; and

4) 15 grams of acetone.

The components were mixed to produce an adhesive with a homogeneouscomposition of approximately 17 wt % solids.

Polyethylene terephthalate (PET) angioplasty balloons, measuring 12 mmin diameter and with a double wall thickness of approximately 0.002 ofan inch, were mounted and sprayed with the adhesive and dried asdescribed in Example 1. The dried adhesive contained approximately 26volume % of bismuth trioxide, and 74 volume % polyurethane. The balloonswere then wrapped helically with Pebax® film and laminated under heatand pressure as described in Example 1 to produce consolidated laminatedballoons.

The result was a radiopaque angioplasty balloon with a double wallthickness of 0.0046 of an inch. The balloons were examined by x-rayimaging and showed excellent visibility without the need to fill themwith contrast media.

Example 3

A radiopaque laminating adhesive was prepared by adding the followingcomponents into a plastic mixing container:

1) 297 grams of a polyurethane laminating adhesive available asTecoflex® 1-MP adhesive;

2) 146 grams of bismuth trioxide powder;

3) 119 grams of MEK; and

4) 238 grams of acetone.

The components were mixed together briefly and then charged in alaboratory ball mill jar charged with aluminum oxide ceramic balls. Thejar was then rolled on a ball mill roller for 24 hours to reduce theparticle size of the bismuth trioxide, after which the mixture wasremoved from the ball mill and stored in a glass container. The resultwas an adhesive with a homogeneous composition of approximately 18 wt %solids.

Polyethylene terephthalate (PET) angioplasty balloons, measuring 12 mmin diameter and with a double wall thickness of approximately 0.002 ofan inch, were mounted and sprayed with a thin coat of the adhesive anddried as described in Example 1. The dried adhesive containedapproximately 43 volume % of bismuth trioxide and 57 volume %polyurethane. The balloons were then wrapped helically with Pebax® filmand laminated under heat and pressure as described in Example 1 toproduce consolidated laminated balloons.

The result was a radiopaque angioplasty balloon with a double wallthickness of 0.0065 of an inch. The balloons were examined by x-rayimaging and showed excellent visibility without the need to fill themwith contrast media. Because of the higher concentration of bismuthtrioxide in the laminating adhesive, and also because of the thickerlayer of adhesive, the image for these balloons was more intense thanfor the balloons prepared in Example 2.

Example 4

A radiopaque laminating adhesive was prepared by adding the followingcomponents into a glass mixing container:

1) 78 grams of a polyurethane laminating adhesive available as Tecoflex®1-MP adhesive;

2) 78.2 grams of tungsten powder, submicron particle size;

3) 31.3 grams of MEK; and

4) 62.5 grams of acetone.

The components were mixed thoroughly to produce an adhesive having ahomogeneous composition of approximately 25.4 wt % solids.

Polyethylene terephthalate (PET) angioplasty balloons, measuring 12 mmin diameter and with a double wall thickness of approximately 0.002 ofan inch, were mounted and sprayed with the adhesive and dried asdescribed in Example 1. The dried adhesive contained approximately 42volume % of tungsten and 58 volume % polyurethane. The balloons werethen wrapped helically with Pebax® film and laminated under heat andpressure as described in Example 1 to produce consolidated laminatedballoons.

The result was a radiopaque angioplasty balloon with a double wallthickness of 0.006 of an inch. The balloons were examined by x-rayimaging and showed excellent visibility without the need to fill themwith contrast media. Because of the higher concentration of tungsten inthe laminating adhesive and also because of the thicker layer ofadhesive as compared to Example 1, the image for the balloons was moreintense than for the balloons prepared in Example 1.

Example 5

A radiopaque laminating adhesive was prepared by adding the followingcomponents into a plastic mixing container:

1) 308 grams of a polyurethane laminating adhesive available asTecoflex® 1-MP adhesive;

2) 123 grams of cerium oxide powder, 5 micron nominal particle size;

3) 123 grams of MEK; and

4) 246 grams of acetone.

The components were mixed together briefly and then charged into alaboratory ball mill jar charged with aluminum oxide ceramic balls. Thejar was then rolled on a ball mill roller for 24 hours to reduce theparticle size of the cerium oxide, after which the mixture was removedfrom the ball mill and stored in a glass container. The result was anadhesive with a homogeneous composition of approximately 19 wt % solids.

Polyethylene terephthalate (PET) angioplasty balloons, measuring 12 mmin diameter and with a double wall thickness of approximately 0.002 ofan inch, were mounted and sprayed with the adhesive and dried asdescribed in Example 1. The dried adhesive contained approximately 43volume % of cerium oxide and 57 volume % polyurethane. The balloons werethen wrapped helically with Pebax® film and laminated under heat andpressure as described in Example 1 to produce consolidated laminatedballoons.

The result was a radiopaque angioplasty balloon with a double wallthickness of approximately 0.0062 of an inch. The balloons were examinedby x-ray imaging and showed excellent visibility without the need tofill them with contrast media.

Example 6

A radiopaque laminating adhesive was prepared as described in Example 5.Polyethylene terephthalate (PET) angioplasty balloons, measuring 12 mmin diameter and with a double wall thickness of approximately 0.002 ofan inch, were mounted and sprayed with a small amount of the adhesiveand allowed to dry. The layer of adhesive was then wrappedcircumferentially with a 50 denier yarn composed of ultrahigh molecularweight polyethylene (UHMWPE) commercially available as Spectra® yarn.The yarn was applied at a pitch of approximately 50 threads per inch towrap the balloon. The wrapped balloon was then sprayed with additionalradiopaque adhesive sufficient to fill in around the fibers and to coverthem. The balloons were then wrapped helically with Pebax® film andlaminated under heat and pressure as described in Example 1 to produceconsolidated laminated fiber-reinforced balloons.

The result was a fiber-reinforced radiopaque angioplasty balloon with adouble wall thickness of approximately 0.0064 of an inch. The balloonswere examined by x-ray imaging and showed excellent visibility withoutthe need to fill them with contrast media.

Example 7

A radiopaque laminating adhesive was prepared by adding the followingcomponents into a plastic mixing container:

1) 278 grams of a polyurethane laminating adhesive available asTecoflex® 1-MP adhesive;

2) 89 grams of cerium oxide powder, 5 micron nominal particle size;

3) 112 grams of MEK;

4) 223 grams of acetone; and

5) 0.22 grams of a phthalocyanine green pigment.

The components were mixed together briefly and then charged into alaboratory ball mill jar charged with aluminum oxide ceramic balls. Thejar was then rolled on a ball mill roller for 24 hours to reduce theparticle size of the cerium oxide, after which the mixture was removedfrom the ball mill and stored in a glass container. The result was anadhesive with a homogeneous light green colored composition ofapproximately 16 wt % solids.

Polyethylene terephthalate (PET) angioplasty balloons, measuring 12 mmin diameter and with a double wall thickness of approximately 0.002 ofan inch, were mounted and sprayed with a thin layer of the adhesive anddried as described in Example 1. The dried adhesive containedapproximately 38 volume % of cerium oxide and 62 volume % polyurethane.A 50-denier Spectra® yarn was then wrapped circumferentially about theballoon as described in Example 6. The green color of the adhesive layerfacilitated the visualization of the fibers during the wrapping process.Additional radiopaque adhesive was then applied sufficient to fill inaround the fibers and to cover them. The balloons were then wrappedhelically with Pebax® film and laminated under heat and pressure asdescribed in Example 1 to produce consolidated laminated balloons.

The result was a radiopaque angioplasty balloon with a double wallthickness of approximately 0.0057 of an inch. The balloons were examinedby x-ray imaging and showed excellent visibility without the need tofill them with contrast media.

While the present invention has been disclosed with reference to certainembodiments, numerous modifications, alterations, and changes to thedescribed embodiments are possible without departing from the sphere andscope of the present invention, as defined in the appended claims. Forexample, the ranges and numerical values provided in the variousembodiments are subject to variation due to tolerances, due tovariations in environmental factors and material quality, and due tomodifications of the structure and shape of the balloon, and thus can beconsidered to be approximate and the term “approximately” means that therelevant value can, at minimum, vary because of such factors.Accordingly, it is intended that the present invention not be limited tothe described embodiments, but that it has the full scope defined by thelanguage of the following claims, and equivalents thereof.

1. A balloon, comprising: a first balloon wall layer disposed about alongitudinal balloon axis; a second balloon wall layer disposed on anexterior of the first balloon wall layer; an adhesive disposed betweenthe first balloon wall layer and the second balloon wall layer, theadhesive having a radiopaque property.
 2. The balloon of claim 1, theadhesive disposed along an entire length or circumference of theballoon.
 3. (canceled)
 4. The balloon of claim 1, wherein the first orsecond balloon wall layer comprises a fiber layer. 5.-6. (canceled) 7.The balloon of claim 1, the adhesive having an adhesive base and aradiopaque material distributed in the adhesive base. 8.-11. (canceled)12. A balloon, comprising: a balloon wall having first and secondballoon wall layers and a radiopaque-infused adhesive disposed betweenthe first and second balloon wall layers, the balloon having a firstradiopacity in a first inflation state and a different secondradiopacity in a second inflation state, a third radiopacity of theballoon wall remaining constant between the first and second inflationstates, the first or second radiopacities being a factor of the thirdradiopacity. 13.-14. (canceled)
 15. The balloon of claim 12, the balloontransitioning between the first and second inflation states with aninflation fluid that does not contain a radiopaque material.
 16. Theballoon of claim 12, the factor of the third radiopacity being derivedfrom the positioning of one portion of the balloon wall behind anotherportion of the balloon wall in a view generated by an imaging device.17. The balloon of any of claim 12, the factor of the third radiopacitybeing derived from the folding of the balloon wall.
 18. (canceled)
 19. Aballoon, comprising: a balloon wall having first and second balloon walllayers and a radiopaque-infused adhesive disposed between the first andsecond balloon wall layers, the balloon having a deflated radiographicdensity of the balloon and a lesser inflated radiographic density of theballoon. 20.-21. (canceled)
 22. The balloon of claim 19, the deflatedand inflated radiographic densities defined by a radiopacity value ofthe entire balloon related to a total volume value of the balloon. 23.The balloon of claim 22, the radiopacity value of the entire balloonremaining constant between inflated and deflated states of the balloon.24. The balloon of claim 19, the inflated radiographic density of theballoon providing an image intensity that is 35% to 95% of an imageintensity provided by the deflated radiographic density of a fullydeflated balloon. 25.-26. (canceled)
 27. A balloon, comprising: aballoon wall having first and second balloon wall layers and aradiopaque-infused adhesive disposed between the first and secondballoon wall layers, the balloon having a radiopaque image intensitythat decreases as the balloon changes from a deflated state to aninflated state. 28.-130. (canceled)
 131. The balloon of claim 1, whereinthe adhesive secures the inner wall layer to the outer wall layer. 132.The balloon of claim 1, wherein the adhesive comprises an intrinsicallyradiopaque polymeric material.
 133. The balloon of claim 132, whereinthe intrinsically radiopaque polymeric material contains higher atomicweight heteroatoms covalently or ionically bonded into a polymerstructure.
 134. (canceled)
 135. The balloon of claim 1, wherein theadhesive comprises an evenly dispersed radiopaque material.
 136. Theballoon of claim 1, wherein the adhesive comprises a finely dispersedradiopaque material.
 137. The balloon of claim 1, wherein the adhesivecomprises a first polymer material and the inner wall layer of theballoon comprises a second polymer material differing from the firstpolymer material.
 138. The balloon of claim 1, wherein the adhesive isprovided at first and second spaced locations on an exterior surface ofthe first balloon wall layer.
 139. The balloon of claim 1, wherein theadhesive includes a radiopaque powder.
 140. The balloon of claim 1,wherein the adhesive includes a radiopaque material having a submicronparticle size.
 141. The balloon of claim 1, further including a layer ofmarker material.
 142. A catheter including a balloon having a constantballoon wall radiographic density.
 143. The catheter of claim 142,wherein the balloon includes a radiopaque adhesive between a first walllayer and a second wall layer.